Effects of Monopotassium-phosphate, Nano-calcium fertilizer, Acetyl salicylic acid and Glycinebetaine application on growth and production of tomato (Solanum lycopersicum) crop under salt stress

ArticleSalinity problem is increasingly affecting tomato production in Lebanon leading to economic losses. The study investigated the potential effects of nano - Calcium (LITHOVIT®), monopotassium - phosphate (MKP: 0 - 52 - 34) fertilizers, Acetyl salicylic aci d (Aspirin) and the osmoregulator glycinebetaine (GB) on salt tolerance of potted determinate tomato (variety Sila) plants in open - field. Salt stress was induced by irrigation solutions of EC = 2, 4, 6, 8 and 10 mS cm - 1 and MKP (2, 3 and 3.5 g L - 1 ), Aspirin (50, 75 and 100 mg L - 1 ), LITHOVIT® (0.5, 0.75 and 1 g L - 1 ) and GB (4.5, 6 and 7.5 g L - 1 ) were applied through foliar application or fertigation. Comparisons between treated and non - treated plants at each salinity level (control) showed that LITHOVI T® decreased the salinity - induced reductions in stem diameter, leaf area and chlorophyll content. Medium concentrations of LITHOVIT® and Aspirin improved stem diameter and all products except Glycinebetaine improved flower number compared to control. Root dry weight and Root Mass Fraction were mostly enhanced in MKP and Aspirin - treated plants. Best improvement in plant yield (76%) was obtained with low concentrations of MKP and LITHOVIT® at EC = 8 mS cm - 1 due to improvement in fruit number rather than fruit weight. Consequently, LITHOVIT® and MKP showed superior effects under salt stress compared to Aspirin and Glycinebtaine

Synthetic Peptides with Inadvertent Chemical Modifications Can Activate Potentially Autoreactive T Cells

The human CD8+ T cell clone 6C5 has previously been shown to recognize the tert-butyl-modified Bax161–170 peptide LLSY(3-tBu)FGTPT presented by HLA-A*02:01. This nonnatural epitope was likely created as a by-product of fluorenylmethoxycarbonyl protecting group peptide synthesis and bound poorly to HLA-A*02:01. In this study, we used a systematic approach to identify and characterize natural ligands for the 6C5 TCR. Functional analyses revealed that 6C5 T cells only recognized the LLSYFGTPT peptide when tBu was added to the tyrosine residue and did not recognize the LLSYFGTPT peptide modified with larger (di-tBu) or smaller chemical groups (Me). Combinatorial peptide library screening further showed that 6C5 T cells recognized a series of self-derived peptides with dissimilar amino acid sequences to LLSY(3-tBu)FGTPT. Structural studies of LLSY(3-tBu)FGTPT and two other activating nonamers (IIGWMWIPV and LLGWVFAQV) in complex with HLA-A*02:01 demonstrated similar overall peptide conformations and highlighted the importance of the position (P) 4 residue for T cell recognition, particularly the capacity of the bulky amino acid tryptophan to substitute for the tBu-modified tyrosine residue in conjunction with other changes at P5 and P6. Collectively, these results indicated that chemical modifications directly altered the immunogenicity of a synthetic peptide via molecular mimicry, leading to the inadvertent activation of a T cell clone with unexpected and potentially autoreactive specificities

Molecular basis for functional switching of GFP by two disparate non-native post-translational modifications of a phenyl azide reaction handle

Through the genetic incorporation of a single phenyl azide group into superfolder GFP (sfGFP) at residue 148 we provide a molecular description of how this highly versatile chemical handle can be used to positively switch protein function in vitro and in vivo via either photochemistry or bioconjugation. Replacement of H148 with p-azido-L-phenylalanine (azF) blue shifts the major excitation peak ∼90 nm by disrupting the H-bond and proton transfer network that defines the chromophore charged state. Bioorthogonal click modification with a simple dibenzylcyclooctyne or UV irradiation shifts the neutral-anionic chromophore equilibrium, switching fluorescence to the optimal ∼490 nm excitation. Click modification also improved quantum yield over both the unmodified and original protein. Crystal structures of both the click modified and photochemically converted forms show that functional switching is due to local conformational changes that optimise the interaction networks surrounding the chromophore. Crystal structure and mass spectrometry studies of the irradiated protein suggest that the phenyl azide converts to a dehydroazepine and/or an azepinone. Thus, protein embedded phenyl azides can be used beyond simple photocrosslinkers and passive conjugation handles, and mimic many natural post-translational modifications: modulation though changes in interaction networks

Brain network modules of meaningful and meaningless objects

Network modularity is a key feature for efficient information processing in the human brain. This information processing is however dynamic and networks can reconfigure at very short time period, few hundreds of millisecond. This requires neuroimaging techniques with sufficient time resolution. Here we use the dense electroencephalography, EEG, source connectivity methods to identify cortical networks with excellent time resolution, in the order of millisecond. We identify functional networks during picture naming task. Two categories of visual stimuli were presented, meaningful (tools, animals) and meaningless (scrambled) objects. In this paper, we report the reconfiguration of brain network modularity for meaningful and meaningless objects. Results showed mainly that networks of meaningful objects were more modular than those of meaningless objects. Networks of the ventral visual pathway were activated in both cases. However a strong occipitotemporal functional connectivity appeared for meaningful object but not for meaningless object. We believe that this approach will give new insights into the dynamic behavior of the brain networks during fast information processing.Comment: The 3rd Middle East Conference on Biomedical Engineering (MECBME'16

An unexpected co-crystal structure of the calpain PEF(S) domain with Hfq reveals a potential chaperone function of Hfq

Calpain is a Ca2+-activated, heterodimeric cysteine protease consisting of a large catalytic subunit and a small regulatory subunit. Dysregulation of this enzyme is involved in a range of pathological conditions such as cancer, Alzheimer's disease and rheumatoid arthritis, and thus calpain I is a drug target with potential therapeutic applications. Difficulty in the production of this enzyme has hindered structural and functional investigations in the past, although heterodimeric calpain I can be generated by Escherichia coli expression in low yield. Here, an unexpected structure discovered during crystallization trials of heterodimeric calpain I (CAPN1C115S + CAPNS1ΔGR) is reported. A novel co-crystal structure of the PEF(S) domain from the dissociated regulatory small subunit of calpain I and the RNA-binding chaperone Hfq, which was likely to be overproduced as a stress response to the recombinant expression conditions, was obtained, providing unexpected insight in the chaperone function of Hfq

Identification of a superagonist variant of the immunodominant Yellow fever virus epitope NS4b214-222 by combinatorial peptide library screening

The CD8 T cell response to the HLA-A2-restricted epitope LLWNGPMAV (LLW) of the non-structural protein 4b of Yellow Fever Virus (YFV) is remarkably immunodominant, highly prevalent and powerful in YFV-vaccinated humans. Here we used a combinatorial peptide library screening in the context of an A2/LLW-specific CD8 T cell clone to identify a superagonist that features a methionine to isoleucine substitution at position 7. Based on in silico modeling, the functional enhancement of this LLW-7I mutation was associated with alterations in the structural dynamics of the peptide in the major histocompatibility complex (pMHC) binding with the T cell receptor (TCR). While the TCR off-rate of LLW-7I pMHC is comparable to the wild type peptide, the rigidity of the 7I peptide seems to confer less entropy loss upon TCR binding. This LLW-7I superagonist is an example of improved functionality in human CD8 T cells associated with optimized ligand rigidity for TCR binding and not with changes in TCR:pMHC off-rate kinetics

In silico and structural analyses demonstrate that intrinsic protein motions guide T cell receptor complementarity determining region loop flexibility

T-cell immunity is controlled by T cell receptor (TCR) binding to peptide major histocompatibility complexes (pMHCs). The nature of the interaction between these two proteins has been the subject of many investigations because of its central role in immunity against pathogens, cancer, in autoimmunity, and during organ transplant rejection. Crystal structures comparing unbound and pMHC-bound TCRs have revealed flexibility at the interaction interface, particularly from the perspective of the TCR. However, crystal structures represent only a snapshot of protein conformation that could be influenced through biologically irrelevant crystal lattice contacts and other factors. Here, we solved the structures of three unbound TCRs from multiple crystals. Superposition of identical TCR structures from different crystals revealed some conformation differences of up to 5 Å in individual complementarity determining region (CDR) loops that are similar to those that have previously been attributed to antigen engagement. We then used a combination of rigidity analysis and simulations of protein motion to reveal the theoretical potential of TCR CDR loop flexibility in unbound state. These simulations of protein motion support the notion that crystal structures may only offer an artifactual indication of TCR flexibility, influenced by crystallization conditions and crystal packing that is inconsistent with the theoretical potential of intrinsic TCR motions

Diversity within the adenovirus fiber knob hypervariable loops influences primary receptor interactions

Adenovirus based vectors are of increasing importance for wide ranging therapeutic applications. As vaccines, vectors derived from human adenovirus species D serotypes 26 and 48 (HAdV-D26/48) are demonstrating promising efficacy as protective platforms against infectious diseases. Significant clinical progress has been made, yet definitive studies underpinning mechanisms of entry, infection, and receptor usage are currently lacking. Here, we perform structural and biological analysis of the receptor binding fiber-knob protein of HAdV-D26/48, reporting crystal structures, and modelling putative interactions with two previously suggested attachment receptors, CD46 and Coxsackie and Adenovirus Receptor (CAR). We provide evidence of a low affinity interaction with CAR, with modelling suggesting affinity is attenuated through extended, semi-flexible loop structures, providing steric hindrance. Conversely, in silico and in vitro experiments are unable to provide evidence of interaction between HAdV-D26/48 fiber-knob with CD46, or with Desmoglein 2. Our findings provide insight into the cell-virus interactions of HAdV-D26/48, with important implications for the design and engineering of optimised Ad-based therapeutics

Alzheimer's disease-associated P460L variant of EphA1 dysregulates receptor activity and blood-brain barrier function

INTRODUCTION: Genome-wide association studies link susceptibility to late-onset Alzheimer's disease (LOAD) with EphA1. Sequencing identified a non-synonymous substitution P460L as a LOAD risk variant. Other Ephs regulate vascular permeability and immune cell recruitment. We hypothesized that P460L dysregulates EphA1 receptor activity and impacts neuroinflammation. METHODS: EphA1/P460L receptor activity was assayed in isogenic Human Embryonic Kidney (HEK) cells. Soluble EphA1/P460L (sEphA1/sP460L) reverse signaling in brain endothelial cells was assessed by T-cell recruitment and barrier function assays. RESULTS: EphA1 and P460L were expressed in HEK cells, but membrane and soluble P460L were significantly reduced. Ligand engagement induced Y781 phosphorylation of EphA1 but not P460L. sEphA1 primed brain endothelial cells for increased T-cell recruitment; however, sP460L was less effective. sEphA1 decreased the integrity of the brain endothelial barrier, while sP460L had no effect. DISCUSSION: These findings suggest that P460L alters EphA1-dependent forward and reverse signaling, which may impact blood-brain barrier function in LOAD. Highlights: EphA1-dependent reverse signaling controls recruitment of T cells by brain endothelial cells. EphA1-dependent reverse signaling remodels brain endothelial cell contacts. LOAD-associated P460L variant of EphA1 shows reduced membrane expression and reduced ligand responses. LOAD-associated P460L variant of EphA1 fails to reverse signal to brain endothelial cells.Neuroscience and Mental Health Research Institute (NMHRI), Cardiff University and Sir Geraint Evans Cardiovascular Fund, Cardiff University (grant to A.A. and A.J.R.), L.E.T. by UK Dementia Research Institute, Cardiff University, O.R.M. by School of Medicine, Cardiff University, S.S. and C.L.T. by Eli Lilly (grant to J.W. and A.A.), and C.C. by School of Cellular and Molecular Medicine, University of Bristol. The Bioflux 200 was funded by the Leukemia Research Appeal for Wales, and iBright 1500 was funded by the Ser Cymru II programme (grant CU209 to V.K. and Manon Pritch, which was partially funded by Cardiff University and the European Regional Development Fund through the Welsh Government (Grant CU209 to V.K. and Manon Pritchard)

Scientific Publications on Primary Biliary Cirrhosis from 2000 through 2010: An 11-Year Survey of the Literature

BACKGROUND: Primary biliary cirrhosis (PBC) is a chronic liver disease characterized by intrahepatic bile-duct destruction, cholestasis, and fibrosis. It can lead to cirrhosis and eventually liver failure. PBC also shows some regional differences with respect to incidence and prevalence that are becoming more pronounced each year. Recently, researchers have paid more attention to PBC. To evaluate the development of PBC research during the past 11 years, we determined the quantity and quality of articles on this subject. We also compared the contributions of scientists from the US, UK, Japan, Italy, Germany, and China. METHODS: The English-language papers covering PBC published in journals from 2000 through 2010 were retrieved from the PubMed database. We recorded the number of papers published each year, analyzed the publication type, and calculated the accumulated, average impact factors (IFs) and citations from every country. The quantity and quality of articles on PBC were compared by country. We also contrasted the level of PBC research in China and other countries. RESULTS: The total number of articles did not significantly increase during the past 11 years. The number of articles from the US exceeded those from any other country; the publications from the US also had the highest IFs and the most citations. Four other countries showed complex trends with respect to the quantity and quality of articles about PBC. CONCLUSION: The researchers from the US have contributed the most to the development of PBC research. They currently represent the highest level of research. Some high-level studies, such as RCTs, meta-analyses, and in-depth basic studies should be launched. The gap between China and the advanced level is still enormous. Chinese investigators still have a long way to go